S. lugdunensis

Staphylococcus lugdunensis is a coagulase-negative staphylococcal species (CoNS) that may be found as a component of the commensal flora on human skin. However, unlike other CoNS, S. lugdunensis has a heightened capacity to cause infection displaying virulence properties that in some respects resemble the prolific pathogen S. aureus. Unfortunately, the true burden of S. lugdunensis infection remains unknown due to misidentification of a fraction of clinical isolates as S. aureus. Akin to S. aureus, S. lugdunensis can cause infections that range from relatively minor skin and soft tissue infections to more serious conditions such as bacteremia, and infective endocarditis. Additionally, infective endocarditis attributed to S. lugdunensis infection can be associated with significant tissue damage and elevated mortality emphasizing the virulent potential of this pathogen. Moreover drug-resistant S. lugdunensis strains with heightened resistance to beta-lactam antibiotics (e.g. oxacillin and methicillin) have emerged which could complicate treatment of infection. Remarkably, despite the recognized clinical significance of S. lugdunensis few virulence factors have been identified and the interaction of S. lugdunensis with immune cells such as macrophages has remained unexplored. The observation that S. lugdunensis can cause serious infection akin to S. aureus suggests that S. lugdunensis overcomes nutritional immunity as well as the innate immune functions of cells such as macrophages. We are investigating the mechanisms by which S. lugdunensis obtains nutrients such as amino acids and iron, as well as the fate of S. lugdunensis after phagocytosis by murine and primary human macrophages. These investigations are a way to begin to understand the interaction with this enigmatic bacterium with the host.